Of course, the Navy’s leadership in finding alternative energy sources is not new. The Navy was among the first to move from sail to steam; it built coaling stations around the globe to support the Great White Fleet, which opened the world to U.S. commerce and diplomacy; the Navy later led the transition to oil to power ships, and more than a half-century ago, developed nuclear power for submarines and surface ships.

Each of these innovative efforts was met with resistance at the time, and calls of “Navy foolishness and excessive spending.” Back then, coal and steam were much more expensive than wind, and nuclear power more than oil, but each provided significant strategic advantages, first to the Navy and then to the nation.

So I am not surprised that today some are questioning the Navy’s latest ambitious goals to enhance the energy independence, efficiency and sustainability of its fleet, which will provide new strategic advantages and potentially improve operational flexibility.

Recently, a group of lawmakers wrote to Secretary of the Navy Ray Mabus, objecting to the latest efforts to “green” the Navy “just for the sake of greening the Navy,” in their words. They further stated that “procuring fuels today at drastically greater costs than market prices is not within the Navy’s mission” and urged Mabus to “capitalize on readily available domestic resources for fuel ... before entering into risky propositions such as biofuels.” Basically, the advice was to take a “business as usual” approach.

But we don’t live in a business as usual world. Our dependence on a single commodity to mobilize most of our fleet is a strategic vulnerability. We know this and so do our enemies. I served for many years on the front lines and witnessed firsthand how readiness decreased each time the price of oil increased. Because we had no alternatives, oil price volatility created significant threats to our security.

Since retiring from the Navy, I have had the privilege of serving with some of America’s most distinguished retired military leaders on the CNA Military Advisory Board. We have intently studied this issue and concluded that one of the most critical, long-term security issues for the United States is our over-dependence on oil.

In a 2009 report, the CNA MAB concluded that “America’s current energy posture constitutes a serious and urgent threat to national security — militarily, diplomatically and economically.” Further, this creates an ongoing unacceptable level of risk to our nation.

Mabus recently noted that “for every dollar charged for a barrel of oil, the Department of Navy spends $30 million.” He further stressed that “when unrest in some oil producing regions broke out last year,” the increased price per barrel drove up “Navy’s fuel bill by over $1 billion.” That increase “that we could not have planned for ... [meant that] our Sailors and Marines steamed less, flew less and trained less.”

The CNA MAB’s latest report highlights that “a sustained disruption of our nation’s oil supply would reverberate through our economy and limit our freedom of movement throughout the country.”

The Iranian threat to close the Strait of Hormuz, choking outgoing oil deliveries, underscores vulnerability on the energy issue. Beyond assuring the free flow of oil, our nation’s and our military’s reliance on a single commodity for fuel reduces combat effectiveness, puts our troops in harm’s way and takes them away from their mission: i.e., to fight, engage and rebuild.

The Navy has been investing in alternative fuel technologies to reduce its vulnerability to price volatility, as well as its dependence on foreign oil and related security and economic risks and, ultimately, to save scarce financial resources and lives.

While there is no “silver bullet” to meet our growing energy needs, there are a lot of “silver buckshot” approaches. Increased domestic production of oil will help, but with only 2-3 percent of the world’s known oil reserves, yet 20-25 percent of global consumption, it will not suffice. Increasing global demand for oil will continue to drive the price of oil higher, regardless of how much we produce domestically. The Navy must look ahead and invest now to ensure that we maintain our strategic advantage and operational flexibility going forward.

Biofuels are not a “risky proposition.” They exist today, and more advanced and efficient bio-based fuels and alternative energy technologies are being developed all the time. They need a steady demand to cause investors to expand the industry. The costs of biofuels are continuing to decline, unlike the current price of petroleum.

Security must trump ideology. The cost of inaction is too high. More sustainable energy solutions also are helping to maintain our global competitiveness and strengthen our foreign policy hand.

“These benefits are time sensitive — waiting for a convenient time to address this [energy security] challenge will weaken us while others continue to gain strength,” as the CNA MAB’s latest report further emphasizes.

The Navy — and our nation — now has an opportunity and an obligation to lead. We can meet the challenges of economic, energy and national security. We can transform these daunting challenges into great opportunities that yield sustained security and prosperity, reduce the likelihood that our troops will have to fight in foreign lands and create a better quality of life for future generations. That is what leadership is all about.

U.S. Navy Retired Vice Admiral Dennis V. McGinn is vice chairman of the CNA Military Advisory Board and president of the American Council on Renewable Energy.